Why?
Good question ... and there is a good answer.
Why fast? Because things aren't right with this world.
Things aren't right with you either.
There is an ancient tradition of fasting in order to get things right. Fasting doesn't make things right. It helps you see how to make things right.
In the past, fasting was associated exclusively with guilt and penance. However, the more important reason to fast as Jesus' disciples is because Jesus fasted. Today's gospel tells of Jesus' fasting in the desert. The 40 days of Lent are a reflection of his 40 days of prayer and fasting in the desert.
Why did he fast? What was the vision, the discipline, the strength he found in his holy fast? Jesus didn't fast because of guilt or the need to do penance, but because he wanted to see his own life and calling more clearly and be strengthened for his mission.
The reason for fasting is not to do bad things to yourself to make God happy. The reason for fasting is precisely to let the Lord into your life all day long.
Fasting can do that. You need to see the meaning of your own life more clearly, to recognize your hunger for God, and to be strengthened in your baptismal mission.
A holy fast can help you to experience the presence of God. It's the whole reason, the only religious reason for fasting.
- Little Black Book, Diocese of Saginaw